Dental flask



July 3, 195] A, WE BE 2,559,486

DENTAL FLASK Filed Dec. 1, 1950 ill 23 INVENTOR Thur/1215 A. Web]: 21-

ATTORNEY Patented July 3, 1951 UNITED STATES tA'i'llNT' OFFICE DENTALFLASK Thomas A. Wcblier, Hyattsville, Md.

Application December 1, 1950, Serial No. 198,582

6 Claims.

A further object of the invention is to provide a hinged dental flaskhaving small flask sections or cups constructed so that a portion orportions of the invested work ma project outwardly of' the flask, sothat it is unnecessary to embed the entire piece of Work in the moldingmaterial of the cups.

A further object is to provide a dental flask including flask sectionsor cups which are so constructed that it is much easier to dislodge themolding material from the cups and the invested work from the moldingmaterial, than in conventional flasks or mold boxes.

A further object is to provide a hinged dental having novel andsimplified means for resiliently and firmly holding the flask sectionstogether while the work is invested.

A still further object of the invention is to provide a dental flask ofthe above-mentioned character which is highly simplified, rugged anddurable, and quite inexpensive to manufacture.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings, forming a part of this application, and inwhich like numerals are employed to designate like parts throughout thesame,

Figure 1 is a perspective view of a hinged dental flask embodying myinvention, and showing work invested within the same,

Figure 2 is a transverse vertical section taken on line 22 of Figure 1,

Figure 3 is a perspective view of the flask empty and shown partlyopened,

Figure 4 is a plan view of the flask in a completely open or extendedposition,

Figure 5 is a plan View of the flask in the closed position,

Figure 6 is an end elevation of the closed flask, and,

Figure '7 is a side elevation. of the same.

In the drawings, where for the purpose of illustration is shown apreferred embodiment of my invention, the numerals iii and I I designateelongated bars or arms formed of heavy guage sheet metal, metal platestock, or the like. The arms l8 and H have short converging portions [2and 13 near their rear ends, and interfitting hinge knuckles l4 and 15are formed upon the portions i2 and I3 and receive a pintle l6, hingedlyconnecting the arms 19 and H so that they may swing from their closedsubstantially parallel positions, Figure '7, to their fully opened orextended positions, Figure 4. The arms is and l i may thus swingrelative to each other through substantially 189 degrees, and the armsare substantially rigid. The arms in and H are relatively narrow asviewed from the side of the device, Figure '7, and relatively wide andflat transversely, Figure 4. The arm I i may be slightly longer than thearm it, as shown.

The arm II is provided near, and inwardly of its free end and in itsopposite longitudinal edges with a pair of opposed arcuate notches [1,for a purpose to be described. The arm H is further provided near itsfree end with a small opening it? to facilitate hanging up the hingedflask on a nail or the like when it is not in use.

The arm it is provided at its forward or free end and transverse centerwith a hook l9, integral therewith, and the hook as is directedlaterally outwardly and away from the opposed arm II. The hook I!) issubstantially opposite the notches H, as shown.

Near and inwardly of the free ends of the arms l9 and l l, a pair ofopposed channel sections or cups 2!! and 2| have their flat bottoms 22rigidly secured to the inner faces of the arms, by spot welding or thelike. The cups 2!! and 2| extend transversely of the arms It and H andslightly beyond the opposite longitudinal edges of the arms, and theopposite ends of the cups are open. The cups 2% and 2! include flatopposed sides or skirts 23, integral with the bottoms 22 and extendingtransversely of the arms is and l I. The sides 23 project laterallyinwardly of the inner opposed faces of the arms Ill and H, and havestraight longitudinal edges 24, forming stops. The sides 23 of each cupconverge slightly toward the cup bottom 22, so that the molding materialis more readily removable from the cups. The edges 2% of the cups areadapted to meet when the arms ill and H are swung to their closedpositions, and the edges 24 serve as stops to limit the closing of thearms. The arms Ill and H are parallel, as shown, when the edges 24 ofthe cups 2% and 2! are in contact.

The cups 20 and 21 are provided at their opposite ends and in theirbottoms 22 with arcuate recesses or notches 25, extending throughoutsubstantially the entire widths of the cups. The

notches 25 are curved longitudinally of the arms l and ll, as shown. Thesides 23 are rounded at their corners, as at 25. The inner surfaces ofthe cups and 2! are smooth, and all of the;

parts of the device are free from sharp edges, burrs, and the like.

In use, the hinged flask may be swung open to its position shown inFigure 4, and the cups 2!] and 2| filled with plaster of Paris or someother suitable molding material, as shown clearly in Figures 1 and 2.The work W to be invested is now embedded in the plaster of Paris massof one of the cups, while the mass is still soft and one side of thework projects above the mass of plaster of Paris. The flask is now swungto the closed position, Figures 1 and 2, and the edges 24 of the cups 20and 2| contact to limit the closing movement of the arms l0 and II. Animpression is now made in the plaster of Paris mass of the other cup sothat after the plaster of Paris has hardened and the flask is reopened,a complete mold of the invested Work is formed.

In order to firmly yet resiliently secure the cups 20 and 2| in theclosed position, I provide a strong rubber band B, which may be loopedone or more times about the free ends of the arms 10 and II andcriss-crossed one or more times over the closed cups, as shown inFigure 1. Finally, the last loop of the rubber band engages the hook l9and is held in place thereby. The rubber band B may also engage thearcuate notches I! of the arm I I, which tend to further position therubber band so that it will not slip or loosen. This arrangement aiiordsa constant, firm and yetresilient force holding the flask sections orcups together, and there is no liability of exerting too great a forceon the work W, as sometimes happens when positive fastening means, suchas screw-threaded turn buckles, bolts or the like are used fordetachably securing companion flask sections together. Also, the rubberband arrangement is much simpler and more compact, enabling the deviceto be free from moving parts and screw-threaded fastener elements.

As shown in Figures 1 and 2, the work W to be invested may be in theform of a partial upper or lower bar which is generally arcuate in shapeand having two sides each of which may carry one or more teeth. The useof my hinged flask makes it possible to invest one side only of thepartial bar, while the other side projects beyond the cups 2!! and 2|and the mass of molding material. Since the opposite ends of the cups2!] and 21 are entirely open, the work W may extend through either endof either cup, and the arcuate notches 25 in the bottoms of the cupsform additional clearance space to permit the passage of the work or barclose to the side of the adjacent arm ill or II, as shown. The hingedflask of course is adapted for use in investing various types of work inaddition to the partial bar shown in Figures 1 and 2, and theillustration in the drawing is merely illustrative of the manner inwhich a relatively small and curved piece of work is accommodated by theflask.

Since the opposite ends of the cups 20 and 2| are entirely open, it isvery easy to dislodge the plaster of Paris from them. In conventionalflasks having a side or sides extending entirely about the margin of theflask, it is much more diflicult to dislodge the molding material, sincethe marginal side of the flask interferes with the knife or otherimplement used to dislodge the molding material. Also, the open endconstruction of the cups 2B and 2|, which permits the work W to projectbeyond the flask during the investment greatly facilitates dislodgingthe work W from the molding material, Without bending or otherwisedamaging the work, as sometimes happens when it is entirely embedded inthe molding material of a conventional flask.

It is to be understood that the form of the invention herewith shown anddescribed is to be taken as a preferred example of the same, and thatvarious changes in shape, size and arrangement of parts may be resortedto, without departing from the spirit of the invention or the scope ofthe subjoined claims.

Having thus described my invention, I claim:

1. A dental flask comprising a pair of companion channel members whichare generally U-shaped in transverse cross section and have theiropposite ends open, the channel members being shiftable toward and fromeach other, the channel members having sides which are brought intoclose opposed relation when the channel members are shifted together sothat the channel members form an open ended substantially tubular mold,and means connected with the channel members for releasably holding themtogether with their sides in close opposed relation.

2. A dental flask comprising a pair of companion opposed channel memberswhich are hingedly connected and shiftable toward and from each other,the opposite ends of the channel members being open, the channel membersbeing generally U-shaped in transverse cross section and having opposedsides adapted to move into close opposed relation when the channelmembers are shifted together so that the channel members then form anopen ended substantially tubular mold.

3. A dental flask comprising a pair of com panion opposed channelmembers which are hingedly connected and shiftable toward and from eachother, the opposite end of the channel members being open, the channelmembers being generally U-shaped in tranverse cross sec-- tion andhaving opposed sides adapted to move into close opposed relation whenthe channel members are shifted together so that the channel membersthen form an open ended substantially tubular mold, and resilient meansconnected with the companion channel members for releasably holding themtogether with their sides in close relation.

4. A dental flask comprising a pair of hingedly connected arms which areswingable from extended to laterally opposed positions, and companionopposed channel members secured to corresponding sides of the arms andextending transversely of the arms, the opposite ends of the channelmembers being open so that Work invested in either channelmember mayextend be yond either end of the same, the channel members havingopposed sides adapted to substantially contact when the arms are swungto their laterally opposed positions, whereby the channel members forman open ended substantially tubular mold extending transversely of thearms.

5. A dental flask comprising a pair of hingedly connected arms which areswingable from extended to laterally opposed positions, companionopposed generally U-shaped channel members secured to the arms andextending tranversely thereof and having their opposite ends open, thechannel members having sides projecting beyond eorresponding sides ofthe arms and adapted to contact when the arms are swung to theirlaterally opposed positions for forming a substantially tubular openended mold extending tranversely of the arms, the channel membersincluding bottom webs arranged next to and secured to the arms andhaving their ends projecting beyond the opposite longitudinal edges ofthe arms, there being notches formed in the ends of the bottom webs toprovide clearance for work invested within the flask, and meansconnected with the arms for releasably holding them in their laterallyopposed positions.

6. A hinged dental flask comprising a pair of arms hingedly connectednear corresponding ends and adapted to swing to opened and closedpositions, a hook element secured to one arm near its free end, theother arm being provided near its free end and in its longitudinal edgeswith notches arranged substantially opposite the hook element when thearms are in their closed substantially parallel spaced positions, thehook element and notches being engaged by a flexible element forsecuring the arms in their closed positions, and opposed cups secured tothe arms between their ends and including sides extending transverselyof the arms and having substantially straight edges adapted to contactwhen the arms swing together to limit the closing of the arms, the endsof the cups being open, the cups having their ends arranged near theopposite longitudinal edges of the arms.

THOMAS A. WEBBER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 256,879 Carpenter Apr. 25, 1882565,326 Bragg Aug. 4, 1896 1,972,238 Reiilel Sept. 4, 1.934

